2 questions

the puter will advance the ignition timing XX degrees from the base timing you set. so lets say (making numbers up here) that with base timing at 10*, total timing would be 40* (delta 30*). by advancing the base timing to 14*, the total timing would be 44* (still the 30* delta, but the initial 4* advance shifted the timing points across the board).

any codes (the CEL does not need to be on to have a code stored). i would go over the ignition (plug wires specifically) for the sporatic miss. it could be a lot of things though.

good luck.

Our comps only pull timing during shifts.